In order to properly control weeds they must be actively growing. Stresses like, drought, previous in-crop herbicide applications, or pests can stress weeds for a period of time. If Roundup Transorb HC is sprayed during this time, it will not properly translocate down to the roots and therefore result in reduced control of the weeds.

To properly assess when your crop is ready to be sprayed, you can use the thumbnail test or the visual colour test. When your crop has 30% or less moisture content a thumbnail impression will remain on the kernel, and that is what you are looking for. For the visual test, download a copy of the Preharvest Staging Guide for recommendations.

Some years you may have a field where the crop is in various stages of maturity. Using Roundup preharvest may help even that crop out. A good general rule to follow is that at least 80% of the field should be at 30% moisture or less. So when making the decision on when to spray, you need to look at the whole field not just one small area.

Some growers want a fast dry down of their weeds and crops, especially in pulse crops. Roundup is slower than a desiccant and should be used primarily for perennial weed control. A desiccant is a contact herbicide, whereas Roundup, when sprayed on the leaves moves through the plant down to the root giving below ground and above ground control. That's why the dry down is slower.